Vacuum cleaner motor fan unit



July 9, 1963 A. L. SEBOK ETAL 3,096,929

VACUUM CLEANER MOTOR FAN UNIT Filed Feb. 1, 1962 FIG. l 30 33 R FIG.3

H6. 2 INVENTORS ALBERT L. SEBOK & FRANK z. DAUGHERTY ATTORNEYS United States Patent 3,096,929 VACUUM CLEANER MOTOR FAN UNIT Albert L. Sebok, Tallmadge, and Frank Z. Daugherty, Kent, Ohio, assignors to Ametek, Inc, New York, N .Y., a corporation of Delaware Filed Feb. 1, 1962, Ser. No. 170,447 6 Claims. (Cl. 230-117) The present invention is concerned generally with a motor-fan unit especially one intended for use in a vacuum cleaner or similar environment, and more particularly with a reversed flow type unit; that is, a unit of the type described, wherein there is established a path for air traversing first .a motor section of the unit, and thereafter the vacuum fan section of the unit.

In the case of a unit including a commutator type motor, the air first traverses the brushes and commutator; thereafter the stator or field, interiorly or exteriorly or both; and, of course, with interior traverse of the field, also passes the exterior of the rotor or armature.

The reversed air flow arrangement as such has well known characteristics. Since air available for motor cooling is not, as in the case of direct flow units, preheated by passage through the fans of air impellers, it allows higher operational power levels for the motor. Also for certain vacuum cleaner environments, the geometry of the reversed-flow motor-fan unit structure is advantageous in allowing a more compact overall cleaner structure.

However, in a reversed flow unit, a loss in fan efiiciency results in consequence of the heating of air passed first through the motor, and also a noisier operation, because of the absence of a certain fan-noise muffling elfect usually present in a direct flow unit by the passage of the fan-discharged air through the motor-untoward results ameliorated in some prior art motor-fan units by use of an adequate diffuser construction at the fan discharge. Nonetheless even in such units as have diffusers with fixed vanes, cavitation of air pulsation occurs at some rates of air discharge.

An object of the present invention is to provide a compact reversed-flow type motor-fan unit construction with a relatively small number of parts and having a diffuser system for the fan discharge.

Another object is to provide a reversed-flow motor-fan unit of increased etficiency, reduced noise and with little tendency to cavitation within its operating range.

A further object is the provision of a plural stage motorfan unit with an improved inter-stage air guide vane assembly mounting.

Other objects and advantages of the invention will appear from the following description and the drawings, wherein:

FIG. 1 shows a motor-fan unit embodying the present invention partially in side elevation and partially in axially longitudinal section taken at about 90 from the elevation with certain parts being omitted for clearer representation of the structure characteristic of the invention;

FIG. 2 is a detailed view showing the angular relations of diffuser vanes in the outlet of the unit; and

FIG. 3 is a detailed view showing a modification in the manner of mounting certain internal elements of the fan.

As shown in the drawings the vacuum cleaner motorfan unit of this invention comprises the motor M and the fan section F wherein a fan housing base element and a bearing supporting bracket or frame end member in the motor frame are incorporated as integral parts of a single member designated by the general reference character in an overall arrangement similar to that appearing in the Cole Patents 2,713,455, 2,822,122, or more particularly with respect to its reversed air flow arrangement similar to 2,888,192.

Thus the motor section of the unit, here shown as a commutating motor, is comprised of the member 10 having two sets of the diametrically disposed projections 11, 12 extending outwardly from a main disk-like portion 13 and equi-spaccd from a bearing receiving socket formation 14, a field core structure including a wound stack 15 of iron laminations supported on the projection 11, 12, a commutator end bracket 17 supporting a diametrically opposed pair of brush holder units 18 and including a bearing socket formation 19, and a rotor 20 shown as an armature having a shaft 21 rotatably supported by hearing units 22 and 23 in the socket formation 14 and 19 respectively. Here the conventional field windings and brush leads are omitted for clarity of representation.

The end portions of the projections 11, 12 have interior arcuate rabbets, co-axial with the bearing socket 14 and therefore with shaft 21, engaging the radial end face and circular arcuate portions or cylindrical portions of the core 15 while the commutator end bracket 17 has a rabbeted rim formation at 24 similarly engaged with the opposite end of the field core. The field wre 15 has a generally cylindrical circumference at least at the end portions, though it may be flattened or have longitudinal grooves and the like for accommodation of coil end securing strips and the like.

The components of the motor portion are secured together by a pair of diametrically opposed bolts 27 passed exteriorly of the core 15 through corresponding bosses 28 of the commutator end bracket and threaded into the ends of the projections 11 of one set. In the case of a commutator motor, as here shown, the bosses 28 have bolt receiving arcuate slots concentric with the shaft of the rotor or with the axis of the socket 19 permitting a limited rotational adjustment or setting of the brushes relative to the poles of the core 15, for which purpose prefera-bly there is also included means (not shown) for locating the core 15 in rotational sense in a definite position relative to member 10. As thus far described the motor structure is generally similar to that of the aforementioned Cole patents.

Means of conventional and known type may be included between the outer races of the bearing units and end wall of the bearing sockets for retaining lubrication, and so also spring means acting on the outer races to preload the bearings for quieting of bearing operation, permitting some slight axial float of the rotor 2G.

The disk portion 13 of member 10 provides an end wall for the fan housing and through an offset portion 30 supports an axially extending or cylindrical flange portion 31 and through a short radial wall portion 32 on the external circumference of 31 also supports a backwardly ofi'set mounting rim 33.

Outside of the flange 31 there is provided a circumferentially spaced series of integral vanes or ribs 34 (see also FIG. 2) running endwise out from the right face of wall portion 32. These vanes are preferably disposed with center planes at 45 to respective axial planes of the unit passing through their external edges, and in a typical case twenty-five equally spaced ribs are used.

These vanes also support a drawn sheet metal, somewhat cup shaped, second stage fan housing 36, the outer ends being sloped at 37 to facilitate the fitting of the cylindrical wall portion 36a of the shell on the vanes. Preferably at vanes 34, member 10 is turned down to form a shoulder 38 against which the edge of wall 36:: abuts on each vane, and also outwardly from the shoulder a notch 39 whereby the edge of the wall 36a may be staked inwardly at a plurality of the vanes, as at 40 in FIG. 1, to retain the entire shell 36 axially in position. Also for this purpose the vanes may be somewhat thickened at the locations where the staking is to occur as at the vane 34a in FIG. 1, and additionally the shell edge may be staked or sheared downwardly on opposite sides of the vane as at 41, 41 to prevent rotational displacement of the shell.

The interior peripheral edge of flange 31 may be rabbeted at 43 to an axial depth somewhat greater than and providing a seat for the edge of an annular sheet metal baffle disk 45 further described hereinafter. Again the edge of the flange outward of the rabbet 43 may be staked inwardly for retention of the plate 45.

The annular plate 45 and the portions 13, 30 and flange 31 provide a first stage housing or chamber having a central air inlet 47 spanned by a plurality of integral webs or spider formations continuous with the reinforcing rib-s 29 on the back face of disk 13 and running out approximately to the rim 33 for support in central location of the bearing socket 14.

The construction of the indentical fan impellers or rotors 50, 51 respectively for the first and second fan stages, and the clamping of the same on the motor shaft are well known and conventional. Each impeller comprises a sheet metal disk 52 centrally apertured to receive the motor shaft, a plurality of spaced vanes 53 and an annular sheet metal disk 54 having an opening or impeller inlet by virtue of the large aperture of the annular disk at the edge of which the inner ends of the vanes 53 are located.

The inner race of bearing unit 22 at one end abuts against a shoulder on the rotor of the motor, the end of the cylindrical portion of a flanged collar 56 abuts against the other end of the inner race, the first stage impeller disk 52 is sandwiched between the flange of collar 56 and a spool-like spacer element 58, the disk 52 of impeller 51 is sandwiched between the spool 58, and a clamping washer 59 and all elements are clamped on the shaft by clamping nut 60 tightened down the threaded end of shaft 21 projecting from the motor proper into the fan unit. A stationary vane and baifie assembly, again of known and conventional general form includes an annular disk 62 having a central aperture closely spaced with running clearance from one end of spool 58, a series of like circumferentially spaced guide vanes 63, and the plate 45 assembled into a unit supported in the fan housing by the connection or seating of the plate 45 as previously described; While the plate 45, as a first stage discharge outlet, has a large central opening, similar in form to that of the impellers and located at about the middle of the arcuate cross-sectioned circumferential groove provided in the spool 58 as an air guide means turning and guiding the air discharging from the first stage into the impeller inlet of the second stage.

The end wall of the shell 36 is centrally dished out- Y wardly at 36b and has a central aperture closed by a removable plug disk 65 to provide access to the clamp ing nut 60 for purposes of balancing the impeller and motor assembly.

FIG. 3 shows a modification in the mounting of the stationary guide vane assembly on the flange 31. Here the free edge of the flange 31 is rolled or deformed inwardly to provide an inwardly extending bead or lip 70, and the plate 45 along its perimeter has a folded portion generally V-shaped in cross-section providing a peripheral rim portion 72 generally cylindrical in external form to conform to the interior of flange 31, the free edge of the portion 72 being curved inwardly and then reflected radially outwardly at 73 to provide an interlocking engagement with the lip 70, the curvatures being exaggerated at 73 for purposes of clarity. The wall portion 74 into which the plate 45 first is reflected inwardly also has a slope in an axial sense to serve in some degree as a guide element for air entering the outer ends of the vanes of the fixed blades in the first stage chamber.

It will be noted that the offset portion at 30 results in a shallow face recess on the fan side of disk 13 and that the disk 54 of the first stage impeller is just received in this recess; and that the spacing of the flange 31 beyond the circumferences of the first stage impeller and the stationary vane assembly provides a circumferential space for passage of air from the outlet ends of the first stage impeller inter-vane passages into the outer circumference of the stationary vane assembly; while the equally sized discharge opening of the stationary vane assembly and the second stage impeller inlet along with the grooved circumference of the spool 58 provide a passageway from the outlet of the first stage into the impeller inlet of the second stage. Also the circumferential spacing of the cylindrical wall 36a from the discharge at the peripheral circumference of the second stage impeller provides an annular circumferential channel receiving the air discharged by the second stage impeller. This latter described channel or passage discharges air axially through the longitudinal passages provided between wall 360, flange 31 and vanes 34, which air ultimately encounters wall 32 and discharges laterally between the blades 34, wall 32 and the edge of 36a.

With this overall arrangement, a reversed flow is obtained; that is, the air is drawn in and around the motor from the commutator end passing through the commutator bracket around the brushes and between the field core and armature to reach the first stage inlet 47, it also being possible for air to pass around the outside of the motor between posts 1112, the core and the end plate 13 to reach the fan inlet.

We claim:

1. A motor-fan unit of reversed air-flow type comprising: a motor stator; a motor rotor including a shaft; first and second motor end brackets on respective opposite ends of the stator, and having central socket formations supporting bearings for said shaft; the said first bracket having apertures therethrough surrounding the socket therein providing air inlet means; said second bracket being an integral structure including a generally disk-like portion having as for air inlets arcuate apertures around the corresponding bearing socket formation thereof, a rim portion including a cylindrical flange concentric with the socket of the said second member extending endwise outwardly from the motor portion of the unit, and circumferentially spaced diffuser vanes on the cylindrical exterior of said flange; fan impeller means disposed endwise outwardly beyond said flange on an end of said shaft projecting through the said second bracket; and generally cup-shaped fan shell means including an end wall and a cylindrical portion, said cylindrical portion being fitted over a part of the length of said vanes to provide a circumferential series of longitudinally directed air outlet passages from said impeller, said passages opening radially outward of said flange.

2. A vacuum motor-fan unit as described in claim 1, including two fan stages; the said impeller being a second stage impeller; a first stage impeller mounted on said shaft disposed proximate to said disk portion and having a central air inlet receiving air from said arcuate apertures; a stationary interstage air guide vane assembly disposed between said impellers including an annular disk peripherally engaged with said flange and providing a central aperture as a discharge opening to the inlet of the second stage impeller, a second annular disk with a central aperture having a close running clearance relative to the shaft structure, and a plurality of vanes each extending substantially from said central opening to the outer periphery of said second disk.

3. A vacuum motor fan unit as described in claim 2, wherein said flange has an internally rabbeted free edge providing a seat for a peripheral edge of the first said disk in said interstage vane assembly, said peripheral edge being deformed over the vane assembly edge for retention of the latter.

4. A motor-fan unit as described in claim 2 wherein said flange has a free edge off-set inwardly from the generally cylindrical form thereof; and the exterior peripheral edge of the first said disk in said interstage vane assembly includes a rim formation inserted within said flange, said rim formation having a portion deformed inwardly and a second portion reflected outwardly in contact with said flange, the second portion having a groove formation engaged with the free off-set edge of said flange.

5. A motor-fan unit as described in claim 1 wherein said disk-like portion of the second member includes spaced post formations projecting toward and engaging the adjacent end of said stator, thereby to provide access of air over the exterior of the stator to the air inlet formations of said disk portion.

6. A motor-fan unit of reversed air-flow type comprising: a motor stator, a motor rotor including a shaft; first and second motor end brackets on respective opposite ends of the stator and having central socket formations supporting bearings for said shaft; the said first bracket having apertures therethrough surrounding the socket therein providing air inlet means; said second bracket being an integral structure including a generally disk-like portion having arcuate apertures around the corresponding bearing socket formation thereof, a rim portion including a cylindrical flange concentric with the socket of the said second member extending endwise outwardly from the motor portion of the unit, and diffuser vanes on the exterior of said flange; tan impeller means disposed endwise outwardly beyond said flange on an end of said shaft projecting through the said second bracket; and generally cup-shaped fan shell means including an end wall and a cylindrical portion, said cylindrical portion being fitted over a portion of said vanes to provide axially directed air outlet passages from said impeller opening radially outward of said flange; said vanes extending generally parallel to the axis of said shaft, but each being generally obliquely disposed to a plane including the shaft axis and passing approximately through the middle region of the respective vane, each vane having its inner edge advanced into the direction of notational approach of said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,021,298 Fors'berg Nov. 19, 1935 2,280,495 Martinet Apr. 21, 1942 2,713,455 Cole July 19, 1955 2,822,122 Cole Feb. 4. 1958 2,888,192 Cole et a1 May 26, 1959 

1. A MOTOR-FAN UNIT OF REVERSED AIR-FLOW TYPE COMPRISING: A MOTOR STATOR; A MOTOR ROTOR INCLUDING A SHAFT; FIRST AND SECOND MOTOR END BRACKETS ON RESPECTIVE OPPOSITE ENDS OF THE STATOR, AND HAVING CENTRAL SOCKET FORMATIONS SUPPORTING BEARINGS FOR SAID SHAFT; THE SAID FIRST BRACKET HAVING APERTURES THERETHOUGH SURROUNDING THE SOCKET THEREIN PROVIDING AIR INLET MEANS; SAID SECOND BRACKET BEING AN INTEGRAL STRUCTURE INCLUDING A GENERALLY DISK-LIKE PORTION HAVING AS FOR AIR INLETS ARCUATE APERTURES AROUND THE CORRESPONDING BEARING SOCKET FORMATION THEREOF, A RIM PORTION INCLUDING A CYLINDRICAL FLANGE CONCENTRIC WITH THE SOCKET OF THE SAID SECOND MEMBER EXTENDING ENDWISE OUTWARDLY FROM THE MOTOR PORTION OF THE UNIT, AND CIRCUMFERENTIALLY SPACED DIFFUSER VANES ON THE CYLINDRICAL EX-TERIOR OF SAID FLANGE; FAN IMPELLER MEANS DISPOSED END WISE OUTWARDLY BEYOND SAID FLANGE ON AN END OF SAID SHAFT PROJECTING THROUGH THE SAID SECOND BRACKET; AND GENERALLY CUP-SHAPED FAN SHELL MEANS INCLUDING AN END WALL AND A CYLINDRICAL PORTION, SAID CYLINDRICAL PORTION BEING FITTED OVER A PART OF THE LENGTH OF SAID VANES TO PROVIDE A CIRCUMFERENTIAL SERIES OF LONGITUDINALLY DIRECTED AIR OUTLET PASSAGES FROM SAID IMPELLER, SAID PASSAGES OPENING RADIALLY OUTWARD OF SAID FLANGE. 